Fusion Technology Nanopowder Magnetic Fluids

Abstract

Magnetic nanomaterials play an important role in emerging industries, specializing in the study of objects (natural or artificially synthesized) with nanoscale building blocks. The wide use of magnetic nanomaterials (especially for biological applications) is constrained by the following reasons: difficulties in obtaining monodisperse ferromagnet particles with stable reproducible characteristics, high cost of large-capacity production However, nanomaterials with magnetic properties are increasingly used in everyday practice. Some companies have already established the production of the first samples of nanomaterials. The time to conduct of a large-scale search for the ways of practical use of magnetic materials has come. Ferrofluids or so-called magnetic fluids are suspensions of magnetic nanoparticles stabilized with a surfactant, in liquid media. Magnetite and ferrites can act as the magnetic phase in the ferrofluids. The liquid phase is water or an organic liquid. The dimensions of the magnetic nanoparticles are 5-10 nm. The market supplied magnetic fluids contain mostly magnetite. Such magnetic fluids are used as a separation medium, polarized external inhomogeneous magnetic field in the gold mining industry to recover the fractions containing 90-97% native gold. A method for the preparation of a colloidal solution with a narrow distribution of magnetite particles according to the size by the heterogeneous condensation method according to R. Zigmondi has been developed. Condensation is carried out on seeds, which is brought into the solution of nanoparticles of magnetite. Getting monodisperse sol is achieved by injecting a concentrated solution of one component in a very dilute solution of another, with vigorous stirring (typically Veimarn). A method called "double additive" proposed G.J. Fleer and J. Lyklema is used to stabilize the sol. The method reduces to the fact that the source unprotected magnetite sol stabilizer is added to a certain volume of a colloidal solution of magnetite, on the surface of which stabilizer is physically and chemically sorbed.